My invention relates to winch-hoists, and especially to portable winch-hoists, and particularly to that type of hoist in which a main frame, generally box-shaped in form, has a pair of frame arms between which is rotatably mounted a ratchet-driven drum upon which the lifting cable is reeled, and a U-shaped operating lever has arms which span the main frame, being pivoted thereto for swinging movements about the drum axis. Pawls carried by the main frame and lever are selectively cooperable with the drum ratchet to rotate and control the drum when the lever is pivotally actuated. Features of such a winch-hoist are disclosed in U.S. Pat. No. 2,633,328, which issued on Mar. 31, 1953.
The patented hoist, just referred to, has a number of commercially proven advantages, particularly in the construction of, and mode of cooperation between, the ratchet and the pawls. However, it has developed that further significant improvements can be made. For example, in apparatus common in the prior art, it has been necessary to secure the cable to the drum by the use of a slug of metal swaged to an end of the cable and secured to the drum in a recess provided in the drum surface. In such prior apparatus, when the cable required replacement, it has been necessary to cut the cable and in some cases to resort to the use of special swaging tools. Complications involved in this procedure have made it difficult to make cable replacements in the field. Usually it has been easier to return the hoist to a factory facility for replacement.
Prior art apparatus has also suffered from the disadvantage that, when it was desired to double the cable by the use of a pulley-block, which requires coupling the hook-end of the cable to the main frame, the "hook-to-hook" distance, that is the distance from the anchor hook to the load hook on the pulley-block, was substantial, and this correspondingly reduced the available working space beneath the load hook. Also, stresses generated at the point of securement of the doubled cable, which point was heretofore at or adjacent to the lower end of the main frame, have necessitated use of a main frame of a heavier configuration throughout its length, than would otherwise be required for a given load capacity. In addition, to protect user, hoist and load, it has been common to design the manually operable handle, which drives the pawl lever, in such a way as to permit bending of the handle when it was subjected to torque in excess of a predetermined limit. Such bending usually rendered the handle unusable. A further disadvantage was that there has been very limited freedom for variably associating the handle with the lever, or no freedom (in the case of integral lever and handle), frequently resulting in having to operate the winch at a short effective lever arm, when the winch was used in tightly confined positions, and/or making it impossible to have a working stroke in the most advantageous direction.
It is the general objective of this invention to overcome all of the aforesaid problems by provision of improved winch-hoist apparatus in which, although the cable is very securely wound and fastened on the drum under all operating conditions, yet field replacement of the cable is a very simple matter, the double-rigged "hook-to-hook" distance is reduced, frame weight can be minimized, and the handle includes safety and convenience features and operational advantages not previously available. In achievement of these general objectives, I have provided a hoist in which the cable is releasably retained on the drum in novel fashion, being snubbed thereon capstan-fashion, by passing a plurality of turns around the drum and through apertures in the drum structure at two axially-spaced-apart points, it being engaged adjacent at least one of said points by fastening means which prevent the snubbing turns from coming loose.
I have been able to minimize the anchor-to-load distance, when double-rigged, while at the same time making possible the reduction of the weight of the hoist, by providing improved means for attaching the doubled cable to the frame, which means is disposed in an upper location with respect to the frame, e.g., near the anchor hook.
The invention also provides a handle which is not only unique and improved per se, but also cooperable with the hoist at any of four (or more, if desired) angularly related positions, thereby permitting optimization of the operating position and of the "pull angle" without a reduction in leverage; thus avoiding the need for excess effort by the operator. In particular accordance with the present invention, the handle inlcudes a bendable safety link which protects user, load and handle assembly, in the event of serious overloading. Should overloading be encountered, it is only necessary to replace the relatively inexpensive safety link, rather than a complete handle assembly.
The construction is such as to make it very easy to shift the operating position of the handle on the lever, and also very simple to remove and replace the bendable link. It is also a feature, that the handle apparatus of my invention incorporates storage space for spare safety links.